Association Between Geospatial Access to Care and Firearm Injury Mortality in Philadelphia

IMPORTANCE The burden of firearm violence in US cities continues to rise. The role of access to trauma center care as a trauma system measure with implications for firearm injury mortality has not been comprehensively evaluated. OBJECTIVE To evaluate the association between geospatial access to care and firearm injury mortality in an urban trauma system. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study of all people 15 years and older shot due to interpersonal violence in Philadelphia, Pennsylvania, between January 1, 2015, and August 9, 2021. EXPOSURES Geospatial access to care, defined as the predicted ground transport time to the nearest trauma center for each person shot, derived by geospatial network analysis. MAIN OUTCOMES AND MEASURES Risk-adjusted mortality estimated using hierarchical logistic regression. The population attributable fraction was used to estimate the proportion of fatalities attributable to disparities in geospatial access to care. RESULTS During the study period, 10 105 people (910 [9%] female and 9195 [91%] male; median [IQR] age, 26 [21-28] years; 8441 [84%] Black, 1596 [16%] White, and 68 other [<1%], including Asian and unknown, consolidated owing to small numbers) were shot due to interpersonal violence in Philadelphia. Of these, 1999 (20%) died. The median (IQR) predicted transport time was 5.6 (3.8-7.2) minutes. After risk adjustment, each additional minute of predicted ground transport time was associated with an increase in odds of mortality (odds ratio [OR], 1.03 per minute; 95% CI, 1.01-1.05). Calculation of the population attributable fraction using mortality rate ratios for incremental 1-minute increases in predicted ground transport time estimated that 23% of shooting fatalities could be attributed to differences in access to care, equivalent to 455 deaths over the study period. CONCLUSIONS AND RELEVANCE These findings indicate that geospatial access to care may be an important trauma system measure, improvements to which may result in reduced deaths from gun violence in US cities.